I have been using the Internet Archive for several years without any problems.
However, since yesterday I find that I cannot download any items or even view them. This does not apply just to books put up by the National Yiddish Book Center (though most of my downloads are from this source), but to all books irrespective of their uploader.
With the exception of the post to which I am responding, I have been unable to find anyone else with this problem. I suppose this would indicate that the problem lies with my computer rather than with the Internet Archive. If so, I have no idea what that problem might be. If I find out, I shall post the information.